Various techniques are available today in order to repair a sinking, sagging, or broken concrete foundation. Foundation (slab) damage is caused by unstable ground beneath and/or around the foundation. This can be a result of soil conditions, tree roots invading the area, plumbing leaks, poor drainage, etc. To repair the damage, it is usually necessary that pilings or other supports be driven into the ground below the foundation and shimmed to level the slab. This support can come in a variety of forms.
One of the most common forms of foundation leveling or repair is known as the cable technique. In the general cable method, concrete pilings are driven into the ground, one atop another until they reach the point of refusal or at least more stable strata. These pilings generally have a bore or opening extending axially therethrough. A braided metal cable is threaded through the openings in the pilings during driving in order to ensure alignment of the pilings and to ensure the pilings do not buckle during the driving process. The number of pilings required in a cable system is dependent on the needs of the particular foundation and the nature of the soil.
In a typical cable system, an initial piece or starter pile is used. The starter pile is generally of a smaller cross-sectional area than the rest of the pilings to facilitate driving of the pilings into the ground and to achieve a greater depth. In general, it is believed that the greater depth achieved by the pilings, the stronger the foundational support.
As noted, a commonly employed foundation repair system employs a length of cable which extends from the lowermost piling section to the surface. It is important that the depth of the borehole, and hence the depth of the pilings beneath the foundation, can be accurately determined should future repairs be necessary. Accordingly, the end of the cable which sticks out the top of the pilings is generally color coded indicating various lengths of cable. It is important that the cable be securely locked to the starter pile such that it cannot be pulled up through the pilings during or subsequent to the installation process.
Typically, the lowermost end of the braided cable is capped with a fitting and then fixedly secured to the starter pile. The most common form of anchoring the cable is to weld the fitting to the inside of the starter pile, though it may be secured by adhesives or the like as well. Accordingly, the starter pile and cable form a single component.
Rather than have the installers of the cable system perform the welding on site to secure the cable to the starter pile, the cable is sold with the fitting attached and pre-welded to the starter pile. In order to ensure that they have the right length of cable in stock without wasting cable, the installers must pre-purchase a variety of different length cables pre-welded to starter piles, e.g. ten foot, fifteen foot, twenty foot, etc. This can be costly and inefficient for the installers.